Results: Among patients with subthreshold depression at baseline, those seen in clinics with quality improvement programs with special resources for therapy were less likely to have probable depressive disorder and unmet need for care at follow-up, compared with those seen in clinics that provided usual care. Among patients with depressive disorder at baseline, those seen in clinics with quality improvement programs with special resources for medication management were less likely to have unmet need for care at follow-up, compared with those seen in clinics that provided usual care. Patients with subthreshold depression at baseline seen in clinics with a quality improvement intervention were less likely at follow-up to have had a mental health visit (in primary care or specialty care, depending on the intervention) in the prior 6 months.

Conclusions: Relative to usual care, quality improvement interventions improved 57-month outcomes (probable depression, unmet need, or both) for primary care patients with depressive disorder and subthreshold depression and lowered use of mental health visits for those with subthreshold depression. The results highlight the feasibility and utility of including patients with subthreshold depression in such programs.